Regarding noodles, the most well known method as a method of preventing the sticking of slit noodle strings and improving the loosening of the noodle strings is a method of applying dusting powder to the noodle strings immediately after the noodle strings are obtained by slitting. Typically, wheat flour or starch is used as the dusting powder. By causing wheat flour powder or starch powder to adhere to the surfaces of the noodle strings, moisture on the surfaces of the noodle strings is removed, and the slippage of the noodle strings is increased. Especially, in recent years, oxidized starch and acetylated starch are available as the dusting powder. In addition, also available is dusting powder which is obtained by mixing, for example, calcium carbonate with the oxidized starch or the acetylated starch, has a high sticking preventing effect, does not cause a cooking liquid to be too turbid at the time of cooking, and has excellent properties.
However, such dusting powder is basically used for raw noodles and half-dried noodles to prevent the sticking of the noodle strings in a production process and distribution process and at the time of preservation. Such dusting power cannot effectively prevent the sticking of the noodle strings of boiled noodles, steamed noodles, and instant noodles. This is because in the case of the boiled noodles, steamed noodles, and instant noodles having been subjected to gelatinization, the sticking of the noodle strings occurs since the starch on the surfaces of the noodle string turns into paste during the steaming or after the boiling, and the action mechanism of the occurrence of the sticking herein is different from that of the occurrence of the sticking of the raw noodles.
Especially, regarding, for example, chilled distribution noodles obtained by packing boiled noodles or steamed noodles, to prevent the sticking in a distribution stage and preservation stage and improve the loosening at the time of cooking, oil is applied to the surfaces of the noodle strings after boiled or steamed noodle strings are washed in water.
Meanwhile, as a conventional technology of preventing the sticking of the noodle strings of the instant noodles, a device, called a wave box or conduct tube, configured to control the positions of the noodle strings in a vertical direction is attached at a position immediately after a slitter configured to slit into the noodle strings and performs a treatment (waving treatment) of causing the noodle strings to be strongly wavy. By causing the noodle strings to be strongly wavy as above, a large number of spaces are formed among the noodle strings, the noodle strings do not overlap in a vertical direction, and contact portions among the noodle strings can be reduced. Therefore, the sticking of the noodle strings can be prevented significantly. Further, used in recent years is a method of applying, for example, a low-viscosity polysaccharide thickener solution as a loosening improving agent to steamed noodle strings.
However, in the case of hot-air dried noodles, even if the above-described technology is used for the instant noodles, the sticking of the noodle strings tends to occur, and this causes the problem of a loosening property at the time of cooking in some cases. In a case where the above-described waving treatment is not performed with respect to the noodle strings in order to realize less-wavy straight-type noodles (less-wavy noodles not subjected to the waving treatment are hereinafter referred to as “straight-type noodles”), the sticking of the noodle strings is still an important problem. If the sticking of the noodle strings of the instant noodles occurs, it is difficult to loosen the noodles at the time of cooking and eating, and the noodles are not uniformly rehydrated. In addition, sticking portions are not adequately dried in a drying step, and this adversely affects the preserving property of the noodles in some cases.
In addition to the above methods, PTLs 1 to 3 are the technologies of preventing the sticking of the noodle strings of the instant noodles. PTL 1 describes that by a non-fried noodles producing method of steaming the noodles after causing oil-in-water emulsion of edible fat and oil to adhere to the surfaces of the noodle strings, the non-fried noodles having an excellent rehydration property and an excellent texture can be obtained. PTL 2 describes that the sticking of the noodle strings is prevented by coating the surfaces of the noodle strings, which have not yet been steamed, with heat-coagulatable protein and coagulating the protein by the steaming.
Further, PTL 3 describes that the sticking of the noodle strings of the non-fried noodles which are not wavy is prevented, and smooth noodles having excellent viscoelasticity are obtained. PTL 3 discloses the following four methods: (1) kneading is performed under reduced pressure; (2) powdered oil and/or lecithin are added to noodle ingredients; (3) gluten is added to the noodle ingredients; and (4) water, an emulsified oil solution, or a lecithin solution is applied to the surfaces of the noodle strings before the steaming. However, the methods of these conventional technologies do not realize adequate effects or cause the problems of the noodle quality and the noodle making property, so that an excellent sticking preventing method has been required.